Ibipinabant (SLV319, BMS-646,256) is a drug used in scientific research which acts as a potent and highly selective CB1antagonist.[1] It has potent anorectic effects in animals,[2] and was researched for the treatment of obesity, although CB1 antagonists as a class have now fallen out of favour as potential anorectics following the problems seen with rimonabant, and so ibipinabant is now only used for laboratory research, especially structure-activity relationship studies into novel CB1 antagonists.[3][4][5]